Waste Advantage Magazine

Mechanical Biological Treatment (MBT): The new kid on the UK waste management block


Waste management in the United Kingdom (UK) has undergone a revolution in the past 20 years. In 1990, the UK landfilled more than 90 percent of its municipal solid waste (MSW), incinerated about 8 percent and recycled the remaining 2 percent. It had one the highest landfill rates in Western Europe and one of the lowest recycling rates, reflecting the UK’s mining traditions and aggregates industries and the subsequent availability of cheap disposal sites. Twenty years on, in 2010, recycling of materials from MSW has increased to more than 45 percent and landfilling has decreased to only 40 percent with the country achieving the important European Union (EU) target of reducing the amount of biodegradable waste landfilled by 25 percent in 2010, compared with the base year of 1995. This target was set by the EU to reflect the impact that landfilling of organic wastes has on climate change through the emission of methane. However, further reductions in landfilling of the organic/biodegradable waste stream are required over the next decade which will be even more challenging (75 percent reduction on the 1995 baseline by 2020). Failure to meet these targets will result in heavy fines payable by the UK Government to the EU and as such the UK Government has initiated policy and funding support to drive biodegradable materials out of landfill. This has included increasing the landfill tax for every ton of material landfilled from £8 (about $13) in 1995 to £80 (about $130) in 2014, and research projects and central funds to help kick-start the delivery of newer waste treatment technologies.

Currently, there are other non-waste sector drivers influencing the development of newer approaches to the treatment of waste. The UK faces an incipient energy shortage because of its dependence for most of its electricity on aged coal and nuclear power stations, which will reach shut down within the next decade. Investment needed for replacements has not come forward, and the growth in power generation from natural gas in the 1990s is now stagnating as indigenous gas supplies are now dwindling, and the UK relies increasingly on imports from Russia and the Middle East, which raises concern over future security of supply.

In addition, recent events in Japan have almost certainly ruled out a nuclear renaissance for the foreseeable future. The government has also made commitments to reduce greenhouse gas emissions by 80 percent of 1990 levels by 2050, and to do this has established several incentive schemes (the Renewable Heat Incentive [RHI], and the Renewable Obligation Certificates [ROC]) to stimulate investment in renewable energy technologies (see ROC and RHI sidebar, page 37).

Problems to Consider

All this could be good news for developers of the traditional alternative to landfill, namely thermal treatment solutions (energy from waste plants) based on mass-burn incineration, especially as energy recovered from the biomass component of waste is considered to be “renewable” energy. However, there are problems with this solution. Firstly, to be eligible for support through ROCs, electricity from waste incineration has to be through treatment in a certified combined heat and power (CHP) facility. Although such facilities are the norm in continental Europe, in the UK most energy from waste plants generate electricity only. Most new facilities could export heat but users are deterred by the high costs of the associated distribution systems.

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